Two years ago, Bob purchased a 20-year $1,000 par value zero-coupon bond for $311.80. If today (with 18 years to maturity) the bond is priced to yield 4.85%, what is his annualized return if he sells the bond? Hint: Calculate the price of the bond today, and use as FV to calculate the return over 2 years. Your answer should be between 4.02 and 22.46, rounded to 2 decimal places, with no special characters.